Usually a milk shake beverage is made by the use of a special freezer exclusively for the purpose of production by a process comprising steps of whipping, freezing, adding some syrup, shaking, and mixing continuously and in lumps.
Special freezers and shake servers are however, quite expensive and large and hence cannot be installed easily. Such machines are difficult to install especially in ordinary homes or small retail shops.
In small retail shops or the like which cannot afford installation of a shake server, it is sometimes the case that a milk shake is made by mixing ice-cream, milk, fruit sauce et cetera. The ice cream is hardened by reducing the temperature to below -15.degree. C. such that it can no longer be scooped with a spoon. Hence, the ice cream taken out of a freezer or freezing chamber whose inside temperature is approximately -20.degree. C. to -8.degree. C. cannot be mixed with a fruit sauce or the like by a simple mixer or beater and a milk shake beverage can be made only by softening the hardened ice cream by adding a liquid of room temperature such as milk.
A milk shake beverage made by the aforementioned method, however, is a mixture of ice cream with milk, fruit sauce or the like of room temperature, hence it is low in the content of micro-crystalline ice and lacks in icy feeling, and the "feeling to the tongue" is like that of a liquid having ice cream melted therein or an ice cream milk definitely different from the taste of a genuine milk shake which is made by the use of "shake server".
Although the milk shake made by the use of a shake server has a degree of icy feeling due to micro-crystalline ice, in the mid-summer season, for instance, a still further cool, refreshing taste is possibly required. With the milk shake made by mixing ice cream and milk or the like, there is a noted lack in icy feeling, and by far a richer icy feeling is required.
In small retailer's shops or the like, it seems to be theoretically possible to put countless tiny pieces of ice into a shake server, mixer or the like and to shake and mix the ice cream with tiny pieces of ice so that milk shake will be rich in icy feeling to the tongue.
It is, however, extremely difficult to keep tiny pieces of ice at a proper temperature in small retailer's shops. This is the same even when a shake server is used for making milk shake, for storage under proper temperature control of tiny pieces of ice has to be done in small retailer's shops or the like.
If the temperature control in storage of tiny pieces of ice is not proper, a part of the tiny pieces of ice down and if the storage temperature is then lowered to approximately -20.degree. C. to -8.degree. C., the once-melted tiny pieces of ice will stick together and be refrozen. Then, the tiny pieces of ice are refrozen in more or less large blocks and can no longer be mixable and even if mixing is feasible, the taste of the milk shake is bound to be badly spoiled. Hence in small retailer's shops or the like milk shake is actually being made without addition of tiny pieces of ice which need very difficult temperature control.